Disc saw felling heads for tree feller bunchers are well known. These machines typically rotate a relatively large saw blade disc which has teeth mounted around its periphery about a generally vertical axis and advance the blade horizontally through a tree. As the saw blade is advanced through the tree, creating a kerf in the tree trunk, a butt plate supported on the head in close proximity to the upper surface of the saw blade disc enters the kerf to support the tree when it is cut off. Hydraulically actuated arms of the feller buncher embrace the tree to prevent it from falling while it is supported on the butt plate.
Typically, removable teeth that actually do the cutting are mounted at angularly spaced locations about the periphery of these saw blade discs. Prior blades have been symmetrical about a horizontal plane and the kerf cut in the tree has also been symmetrical about that plane. These designs have resulted in a relatively wide disc and tooth which results in a relatively wide kerf and high power required to sever a tree.